Concealed actuating unit for automatically raising and lowering cabinets and the like

ABSTRACT

Unitary frame has guideposts which slidably support a carriage moved by a motor driven chain, the frame being easily installed in a wall opening and concealed by a cabinet on the carriage. One of the guideposts is floatingly mounted to accommodate tolerance accumulation and/or slight misalignment. The motor is reversible and controls therefor include control switches, limit switches and safety switches for stopping the motor in a positive manner at will or automatically without harm to the user or the cabinet. A constant force device provides additional lifting power and minimizes tipping of the cabinet.

United States Patent Skifstrom Apr. 2471 973 154] CONCEALED ACTUATING UNIT FOR 3.043.290 7/1962 Smith ..312/306 x AUTOMATICALLY RAISING AND 3,063,769 11/1962 Graber @1111. ..312 223 LOWERING CABINETS AND THE LIKE Inventor: Walter W. Skifstrom, 1504 W. 173rd Street, Gardena, Calif. 90247 Filed: Dec. 28, 1970 Appl. No.: 101,767

[52] U.S. Cl. ..312/223, 312/247, 312/306 [51] Int. Cl. ...A47b 77/08, A47b 67/02, A47b 57/08 [58] Field of Search ..3 12/223, 247, 249, 312/306, 307

[56] References Cited UNITED STATES PATENTS 2,382,354 8/1945 Wales .1 ..3]2/223 2,879,124 3/1959 Maxfield et a] ..3 12/306 X Primary Examiner-Paul R. Gilliam AttorneyPeter H. Firsht and John H. Crowe Unitary frame has guideposts which slidably support a carriage moved by a motor driven chain, the frame being easily installed in a wall opening and concealed by a cabinet on the carriage. One of the guideposts is floatingly mounted to accommodate tolerance accumulation and/or slight misalignment. The motor is reversible and controls therefor include control switches, limit switches and safety switches for stopping the motor in a positive manner at will or automatically without harm to the user or the cabinet. A constant force device provides additional lifting power and minimizes tipping of the cabinet. I

ABSTRACT 1 Claim, 11 Drawing Figures Patented April 24, 1973 6 Sheets-Sheet l .M m Rfl f 1 mf W W Z Patented A ril 24, 1973 3,729,245

6 Sheets-Sheet 2 Wfi ZZ in Z 5A INVENTOR.

WAZTfF W $145730 1 i E 3 (iii/v M6 0, 1$

Patented April 24, 1973 3,729,245

a Sheets-Sheet 5 I 5 I I [*6 r-7 5-' 124' fi 4 INVENTOR.

ma/445w Patented April 24, 1973 3,729,245-

6 Sheets- Sheet 4 m Maw:

Patented April 24, 1973 6 Sheets-Sheet 6 fl J CONCEALED ACTUATING UNIT FOR AUTOMATICALLY RAISING AND LOWERING CABINETS AND THE LIKE BACKGROUND OF INVENTION The present invention relates to mechanisms for raising and lowering cabinets, banks of shelves, and the like, and more particularly to a new and improved actuating mechanism adapted to be installed between a pair of wall studs and carry a kitchen cabinet or the like which serves to conceal the actuating mechanism.

It has long been recognized that the upper shelves of kitchen cabinets which are fixed to a wall are too high for easy reach and require the assistance of some type of ladder for access thereto, which is an inconvenience and creates a safety hazard. This is particularly true in the case of senior citizens whose strength and steadiness is considerably reduced, due to age. However, if the cabinets are made low enough for easy access, then considerable wall space is lost and the work space on the counter below is also unavailable or hampered by the low level of such cabinet. Having a kitchen cabinet that can be positioned at a low level for easy access thereto and can be raised by power-actuated means to a normal elevated storage position, for full utilization of available wall space and a clear work space below the elevated position of the cabinet, has long been appreciated and various actuating mechanisms to accomplish such objectives have been proposed. However, such proposed mechanisms have not been completely satisfactory for the reasons that where such mechanisms are attached directly to wall studs, mis alignment occurs because of the fact that the wall of the kitchen is not necessarily the flat plane it appears to be and the wall studs are not always perfectly vertical. Because of this, the actuating mechanism is distorted or twisted upon attachment thereto, causing binding and difficulty in the operation of the actuating mechanism.

SUMMARY OF INVENTION It is therefore an object of the present invention to provide a new and improved actuating mechanism for raising and lowering cabinets that will allow maximum use of wall and counter space and provide easy access to the upper shelves of kitchen cabinets without inconvenience or hazard to the user.

Another object of the present invention is to provide an actuating mechanism which can be concealed behind a cabinet or bank of shelves and present a neat appearance.

A further object of the invention is to provide an ac tuating mechanism which is unitary in nature and can be disposed between a pair of normally centered wall studs and attached thereto in a vertical position, regardless of whether or not the wall studs are perfectly vertical.

Still another object is to provide means for easily mounting the actuating unit in a vertical position with a minimum expenditure of energy.

A still further object is to provide an actuating unit having a guided carriage to which a desired height of cabinet, bank of shelves, or the like, can be easily attached, in covering relation to the unit.

Still another object is to provide the unit with guide means for guiding the carriage throughout its vertical movement in a manner which obviates binding and dif- -ficulty during such movement.

A still further object of the invention is to provide positive power means for moving the carriage which can be stopped and held at any point of travel without danger of the cabinet falling or losing its contents.

Still another object is to provide means for controlling the power means which include safety means for stopping the operation of the power means before harm can occur to any item that is in the path of travel of the cabinet during descent thereof, the control means having provision for raising the carriage to disengage the cabinet from the item, after which the item can be removed and travel of the cabinet can resume.

Still another object is to provide a counterbalancing means in association with the motor driven carriage, providing additional lifting power and reducing any tendency of the cabinet or bank of shelves to tip forwardly.

These and other objects and advantages of the present invention are achieved by the provision of a unitary box-like frame including a pair of parallel channel members having laterally extending attachment flanges and inwardly directed flanges, the ends of the latter being connected by a flanged shallow channel member. A rear cover forms a base for an electric motor, a gear box and a drive shaft assembly, which are mounted thereon by channel brackets, the brackets and cover being attachable to the deep channel members. The drive shaft assembly mounts a sprocket about which is trained a drive chain, the drive chain also passing around an idler sprocket mounted on a shaft supported between the deep channel members. The drive chain is attached to a carriage by a boss and link connection, the carriage being in the form of a U- shaped casting having projections that extend into the deep channel members. The carriage projections are provided with nylon bushings which slidably engage a pair of guides mounted in blocks inside each deep channel. One guide is fixed, while the other guide is resiliently connected and mounted to float in a short slot to allow for tolerance accumulation and any misalignment. Also connected to the carriage is a long deflection constant force spring coiled on a spool which is mounted on a transverse bar extending between the channel members. The shallow channel member or hat section acts as a guide for the constant force spring.

The outwardly extending flanges of the deep channel members are adapted to engage and be attached to a wall withthe box-like frame disposed between a pair of wall studs. For rapid and accurate installation, a sheet metal hook in the form of a channel member is first located level and secured in proper position on the wall above the intended location of the frame which is provided with a pair of reverse hook mounting clips adapted to engage with the sheet metal hook when the frame is lifted into place. The laterally extending flanges are then bolted to the wall for holding the frame properly in place, with shimming as necessary. The carriage is provided with a pair of studs for the attachment of a cabinet or bank of shelves thereto which are cabinet. The limit switches are located on one of the deep channel members at the extremes of travelof the carriage to stop the motion thereof independently of the operator. Thesafety switch system includes a plurality of serially connected microswitches, movement of the touch platerelative to the cabinet serving to open at least one of the switches and cut off power to the motor. A push-button switch on thepanel acts as a bypass to override the safety switch system and raise the carriage after power to the motor has been cut off due to opening of a safety microswitch by something under the touch plate. The switch panel also includes an on-and-off power switch, an indicator light, a fuse, a pair of up-and-down control switches, as well as the bypass switch. The switch panel can be mounted on the cabinet or on the wall within convenient reach'of the operator.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an exploded perspective view of the novel actuating unit of the present invention illustrating its relation to a wall opening, in which it is adapted to be mounted, and to a cabinet to which it is adapted to be FIG. 5 is a transverse sectional view on line 5-5 of FIG. 4 illustrating details of the actuating unit and its mounting in relation to the wall and studs, fragmentarily shown.

FIG. 6 is an enlarged fragmentary vertical sectional view generally along line 6-6 of FIG. 4.

FIG. 7 is an enlarged fragmentary vertical sectional view generally along line 7-7 of FIG. 4.

FIG. 8 is an enlarged foreshortened vertical sectional view along line 8-8 of FIG. 4 illustrating the mounting of the floating guide post.

FIG. 9 is a bottom plan view along line 9-9 of FIG. 8.

FIG. 10 is a top plan view along line 10-10 of FIG. 8.

FIG. 11 is a schematic diagram of the switch system and circuitry for controlling the actuating unit.

DESCRIPTION OF EMBODIMENT Referring to the drawings, there is shown in FIG. 1, in exploded perspective, a view of a novel actuating mechanism or unit 12, embodying the rinciples of the present invention and illustrating its relation to a wall opening WO, in which it is adapted to be mounted, and to a cabinet or bank of shelves 13, to which it is connectable for raising and lowering thereof. The wall,

opening is cut in a wall W between a pair of wall studs 4 flangesare provided'with a pair of mounting hooks or clipsl8'ad'apted to hook over a channel-shaped support or hook member 20 secured to the wall W in level position over the wall opening WO.

Frame 14, the makeup of which is later described in greater detail, supports a pair of guide posts 22 and 2 3 on which a carriage 24 is mounted for sliding. The carriage is connected to a link chain 26 by attachment means including a boss 28 on the back side of the carriage. As later made clearer, the chain is driven by a reversible motor 30 controlled by circuitry including a pair of limit switches LS1 and LS2. A long deflection constant force spring 32 is connected to the carriage by bolts 34.

The carriage 24 also has a pair of threaded studs-36 and the cabinet 13 has a back wall 38 which is provided with suitable apertures (not shown) to receive the studs for connection of the cabinet to the carriage. The cabinet also has end walls 40 (only one is shown) and a bottom 42 underneath which is a touch plate 44 having anupstanding wall 46 that surrounds the lower edges of the cabinet. The touch plate is suspended from the cabinet bottom by a plurality of assemblies 48 (only one is shown). Preferably, one each of the assemblies is located in the vicinity of the four corners of the touch plate.

Each of the assemblies 48 includes a safety micros witch 50 and relatively movable parts 51 and 52 screwed or otherwise suitably secured to the cabinet bottom 42 and touch plate 44, respectively, as shown in FIG. 2. The switches 50 are normally closed and each is actuated open by engagement with a cam or tapered portion 53 on the associated part 51 upon movement of the touch plate towards the cabinet bottom.

The switches 50 are in series and are electrically connected to a control panel 54 which can be mounted on the cabinet 13, inside or out, or at a convenient location on the wall W. As shown in FIG. 3, the control panel includes a power control toggle switch PS operable between OFF and ON positions, a power on indicator light L, an electrical fuse F, movement control toggle switches S1 and S2 operable between UP and DN positions, and a bypass push button switch PB, which are electrically connected to the motor 30 and the limit switches LS1 and LS2 by means ofa wiring harness or cable 56. Preferably, the cable is formed with resilient folds or loops 58 which can be spread to accommodate downward movement of the carriage and which retract when-the carriage rises so as to remain hidden by the cabinet or bank of shelves 13.

Inviting attention to FIGS. 4 and 5, the frame 14 is composed of a pair of deep channel members 60 each having one of the aforementioned laterally outwardly extending attachment flanges 16. Each member 60 also has an inwardly extending flange 62 of greater lateral extent, the flanges 62 being secured by screws 64 (FIG. 5) to a flanged channel member 66 of shallower extent which caps the space between the ends of the flanges and is referred to as a hat section. The screws 64 on one 1 of the flanges of the hat section also serve to secure a flanged mounting bracket 68 which mounts the electric motor 30. The other flange 62 has secured thereto, by screws 65,*'a flanged bracket 70 on which is mounted a gear box 72 connected to the motor through a power coupling 74. Extending laterally from the gear box is a shaft 76 to which is secured a sprocket 78. Also mounted on the brackets 68 and 70 are bearing boxes 80 which journal a drive shaft 82 having secured thereto sprockets 84 and 86 (FIG. 4). Trained about the sprockets 78 and 84 is a chain 88, shown in phantom lines. Secured to the back flanges of the brackets 68 and 70, by screws 89, is a rear cover 90 which is also secured, by screws 91, to the backs of the deep channel members 60, as shown in FIG. 5. Dust covers 92 and 93 extend between the members 60, as shown in FIGS. 1 and 4.

A pair of bearing boxes 94 are mounted on the deep channel members 60, as shown in FIG. 4, and journal the ends of an idler shaft 96 on which is secured a sprocket 98. Trained about the sprockets 98 and 86 is the link chain 26, shown in phantom lines. Also mounted on the channel members 60 is a transverse bar 100 which supports, for free retation, a spool 102 on which the spring 32 is coiled. The hat section 66 serves as a guide for the spring.

The spring 32 is preferably of the so-called negator type, manufactured by Hunter Spring Company of Hatfield, Pennsylvania, and described in detail in an article entitled, The Theory and Design of Long-Deflection Constant-Force Elements," in the Transactions of The American Society of Mechanical Engineers for May 1952, at pages 439-450. In essence, the spring is a curved strip of flat spring material which in its relaxed or unstressed condition is in the form ofa tightly wound coil, except for the attachment end thereof, which is attached to the carriage 24 by bolts 34. I-lowever,'when the spring is straightened, it becomes stressed and provides power. Preferably, the spring will have a force of about 100 pounds or about 30 percent of the maximum expected load. Not only does the spring provide lifting power; it also reduces the tendency of the cabinet 13 to tip forwardly.

The link chain 26 is provided with a conventional attachment link 104 which is connected thereto by'a pair of coupling pins 106 and to the boss 28 by dowel pins 108, as shown in FIG. 6.

The carriage member 24 is generally U-shaped and has pairs of bearing bosses or legs 110 which project into the deep channel members 60 and carry nylon bushing bearings 112, best seen in FIGS. 5, 7, and 8. One pair of legs carries a plate 114 on which cams 116 and 118 are adjustably mounted for actuating limit switches LS1 and LS2, respectively.

The nylon bushings 112 in one pair of the bearing bosses 110 are journaled on the guide post 22 which is cylindrical and has its ends fixed to a pair of blocks 120 secured in the associated member 60. The other pair of nylon bushings are journaled on the guide post 23 which is also cylindrical and floatingly mounted for relative movement. For this purpose, the lower end of the guide post 23 is disposed in a slot 122 formed in a mounting block 124 secured to the associated channel member 60, as shown in FIG. 9. The slot 122 is elongated in the direction'of the guide post 22. The lower end of the guide post 23 is retained in the block 124 by means of a transverse pin 126 having ends extending into slots 128 in the block 124 as shown in FIG. 8, the slots being elongated in the same direction as the slot 122, as shown in FIG. 4. The upper end of the guide post 23 has a reduced end portion 130 resiliently mounted between a spring 132 and an adjustable setscrew 134 mounted in a block 136 secured to the associated channel member 60, as shown in FIGS. 8 and 10. The floating guide post 23 is thus capable of some movement to accommodate tolerance accumulation and/or slight misalignment.

The makeup of the frame 14 provides for concurrent assembly of subassemblies thereof. For example, the several parts are properly perforated for receipt of the screws 64, 65, 89 and 91, which are preferably of the self thread cutting type. Brackets 68 and 70, and the operative parts carried thereby, can be secured to the rear cover 90. In the meantime, the channel members 60, and the parts carried thereby, can be assembled, the chain 26 being attached to the boss 28 but uncoupled at some distal link. Afterward, the cover can be secured to the members and the operative parts are properly related, the chain is trained and coupled, and so on.

The reversible electric motor 30 is of the split phase type and the operation thereof is controlled by electrical circuitry schematically illustrated in FIG. 11. The motor has a power winding (not shown) energized by current flow through motor terminals MT1 and MT2. The motor also has a starter winding (not shown) connected to motor terminals MT3 and MT4, the direction of current flow therethrough determining the direction of rotation of the motor.

Inviting attention to FIG. 11, the movement control switches SI and S2 are of the double throw type, the former having three poles P1, P2 and P3, the latter having two poles P4 and P5. The switch S1 has contacts C1, C2, C3, C4, C5 and C6, and in one position of throw, designated by the legend UP, pole Pl engages contact C1, pole P2 engages contact C3, and pole P3 engages contact C5. In the other position of throw, designated by the legend DN, the poles engage contacts C2, C4 and C6, respectively. Switch S2 has similar legends and contacts C7, C8, C9 and C10, pole P4 alternatively engaging the contacts C7 and C8, and pole P5 similarly engaging the contacts C9 and C10.

Limit switches LS1 and LS2 are microswitches, switch LS1 having a pole P6 normally engaged with a contact C11, and switch LS2 a pole P7 normally engaged with a contact C12, for energizing the motor 30. Switch LS2 also has a contact C13 which is engaged by the pole P7 after the latter becomes disengaged from the contact C12. The limit switches are suitably spaced vertically and the cams 116 and 118 are properly adjusted to disengage the poles P6 and P7 from contacts C11 and C12 for determining the upper and lower limits of travel of the carriage 24 and the cabinet 13 carried thereby.

The bypass push-button switch PB is of the normally open type and must be held depressed to complete a circuit therethrough.

Power switch PS is positionable to be open (OFF) or closed (ON) to complete a circuit therethrough.

House current is supplied by power leads 140 and 142, pole P1 of switch S1 and terminal MTl of the motor 30 being connected to the lead 140, and one side of the power switch PS being connected to the lead 142. The other side of the power switch is connected by a lead 144 to the fuse F which is connected to the lead 140 through a resistor R, the light L and a lead 146, arranged in series.

The fuse F is also connected to one side of the pushbutton switch PB by a lead 148 and to one end of the series connected safety microswitches 50 by a lead 150. The other end of the series of switches 50 is connected by a lead 152 to pole P3 of switch S1, the other side of the bypass switch PB also being connected to the pole via leads 154 and 152.

Inviting attention to switch S1, contact C1 is connected by a lead 156 to motor terminal MT4 and is tied to contact C4 by a lead 158; contact C2 is tied to contact C3 by a lead 160; contact C3 is connected by a lead 162 to motor terminal MT3; pole P2 is connected by a lead 164to motor terminal MT2; contact C is connected to pole P4 of switch S2 by a lead 166 and to contact C13 of switch LS2 by a lead 168; and contact C6 is connected by a lead 170 to pole P5 of switch S2. In switch S2, contact C7 is connected by a lead 172 to pole P6 of switch LS1; and contact C is connected by a lead 174 to contact C12 of switch LS2. Pole P7 switch LS2 is connected to pole P2 of switch S1 and motor terminal MT2 by leads 178 and 164.

With the carriage 24 at its uppermost limit of travel, switch LS1 is actuated by cam 116 and pole P6 is disengaged from contact C11, but pole P7 of switch LS2 is engaged with contact C12. Throwing power switch PS to the ON position applies power to pole P3 of switch S1 via the lead 144, the fuse F, lead 150, switches 50 and lead 152. Throwing switches S1 and S2 into the DN position of each, power is applied through pole P3 of switch S1 to contact C6, and through lead 170 to pole P5 of switch S2, then to contact C10 and through lead 174 to contact C12 of switch LS2. With pole P7 of switch LS2 engaging the contact C12, power is applied via leads 178 and 164 to the motor terminal MT2 for energizing the motor power winding (not shown). At the same time, power is applied to pole P2 and contact C4 of switch S1 via leads 178 and 164, then via tie 158 and lead 156 to motor terminal MT4 for energizing the motor starter winding (not shown) in a direction to cause the carriage to travel downwardly.

When the cam 116 has moved away from switch LS1, pole P6 reengages contact C11, but there is no current flow therethrough. At the lower extreme of travel of the carriage 24, cam 118 actuates switch LS2 causing pole P7 to disengage from contact C12 and engage contact C13,'thereby interrupting power flow and deenergizing the windings of the motor 30, causing it to stop with the carriage in its lowermost position. Downward travel can be stopped at any time merely by throwing the power switch PS to OFF position or by reversing either of the switches S1 or S2, but not both.

To return the carriage 24 to its uppermost position, switches S1 and S2 are thrown into the UP position of each. Now power flows from pole P3 of switch S1, via

lead 168 to contact C13 of switch LS2, then through.

pole P7 and leads 178 and 164 to motor terminal MT2. At the same time, current flows through leads 178 and 164 to pole P2 of switch S1, and then via lead 162 to motor terminalMT3 for energizing the motor starter winding (not shown) in a direction opposite from before. This causes the carriage to travel upwardly and cam 118 disengages from switch LSZ permitting pole P7 to reengage contact C12 after disengaging from contact C13. Now a path for power is provided from pole P3 via lead 166, pole P4, lead 172, closed switch LS1, lead 176, pole P7, and leads 178 and 164 to the motor terminals MT2 and MT3 for maintaining operation of the motor 30. When cam 116 actuates switch LS1 open this powerpath is broken and the motor stops with the carriage in its uppermost position. Upward travel can be interrupted at any time by throwing switch PS to OFF position.

Returning to downward travel of the carriage 24, should there be an object, animate or inanimate, under the cabinet 13 preventing travel of the carriage to its lowermost position, engagement of the object with the touch plate 44 causes it to move relative to the cabinet bottom 42 and open at least one of the safety switches 50. This interrupts flow of power to the motor 30 and it stops. To back up the cabinet from the obstructing object, switches S1 and S2 are placed in the UP position and the bypass push-button switch PB is pressed and held down. Now a path is provided for flow of power through the fuse F, lead 148, closed switch PB and leads 154 and 152 to pole P3 of switch S1, for energizing the motor 30 as hereinbefore described in connection with upward travel of the carriage. The obstructing object can then be removed. However, the carriage need not be moved all the way to its uppermost position but only sufficiently for the touch plate 44 to be disengaged from the obstructing object, after which the switch PB can be released and the normal circuit for energizing the motor takes over. The motor can be stopped by throwing switch PS to OFF position or by changing the position of switch S1 or switch S2, or reversed by throwing switches S1 and S2 to the DN positron.

From the foregoing, it is clear that the novel actuating unit of the present invention will stop automatically if it encounters an object which interferes with its downward travel, and does so without damaging the object. Also, it can be moved away from the object without any requirement that the object first be removed. Moreover, the unit automatically stops at extremes of travel and can be stopped at will at any point of travel, upward or downward, or its travel can be reversed.

The unitary makeup of the actuating unit of the present invention and the mounting hooks provide advantages of easy installation with minimum expenditure of energy. The floating guidepost compenstles for tolerance accumulation in the unit and for any misalignment due to the wall surface to which it is attached not being a perfectly flat plane.

It is believed that the operation of the actuating unit of the present invention is clearly apparent and is briefly summarized at this point. Referring to FIG. 1, the wall opening W0 having been formed in the wall W between the wall studs WS, the hook-shaped channel support member 20 is secured to the wall above the opening in level position. The actuating unit 12 is then disposed in the opening with the mounting clips 18 hooked over the support member, after which the flanges 16 are secured to the wall by screw bolt and washer combinations 180, as shown in FIG. 5. This provides for support of the unit without requiring the frame 14 be drawn tightly to the wall and twisted or distorted because of non-planarity of the wall. If necessary or desirable, shims can be employed to minimize distortion or provide clearance.

The cabinet 13 is mounted on the carriage 24, appropriate connections of the cable 56 having been made. With the power switch PS thrown to ON position and the switches 81 and S2 thrown to UP position, the motor 30 will operate to raise the cabinet and automaticallystop it in its uppermost position when limit switch LS1 on the frame 14 is actuated open by cam 116 on the carriage. Switch PS can be thrown to OFF position for stopping the cabinet at any point of travel, and travel can be resumed by reversing the switch.

When switches S1 and S2 are thrown to DN position and switch PS is thrown to ON position, the motor 30 is energized to move the cabinet 13 downwardly. Such downward movement ends when the limit switch LS2 on the frame 14 is actuated by the cam 118 on the carriage 24 or the touch plate 44 is caused to move toward the cabinet bottom 42 and at least one of the switches 50 is opened because of an obstructing object or any other reason. In the case of the latter, the switches S1 and 82 are thrown to UP position and bypass push-button switch PB is pressed and held until the cabinet backs up so that the normal relationship of the touch plate and cabinet bottom are reestablished and switches 50 are closed. The actuating unit 12 can then be operated in the usual manner for stopping the cabinet at any point or reversing its travel, etc. Of course, the obstructing object or other cause of touch plate actuation will have been removed.

There has thus been provided a novel unitary actuating unit for a cabinet or bank of shelves which can be readily installed in a wall opening easily with a minimum of expenditure of energy and is concealed by the cabinet. Also, the makeup of the unit accommodates any tolerance accumulation and/or slight misalignment so as to operate in a reliable manner without binding to dispose the cabinet for convenient access to its contents or in a raised position to provide clear working space therebelow, at will. Moreover, provision has been made for automatic control of the unit including a safety switch system actuated by a touch plate,

whereby harm to the unit or its user is prevented and the unit can be stopped and held at any point in a positive manner upon cutoff of power, from which point travel can be reversed or resumed, as desired. Additional lifting power is provided by a constant force device which also tends to keep the cabinet from tipping.

Although the present invention has been herein shown and described in considerable detail in what is believed to be the most practical and preferred em bodiment thereof, it is to be understood that many variations thereof are possible and that the present invention is not to be limited to such details but is to be considered in its broadest aspects and accorded the full scope of the appended claims.

Having described the invention, what is claimed as new and desired to be secured by Letters Patent is:

l. Unitary actuating means for lowering and raising a cabinet and the like, comprising:

unitary frame means including a pair of interconnected parallel channel side members disposable substantially vertically between the facing sides of a pair of studs in a wall of a housing construction, each member having a laterally extending flange securable to said wall; I a vertical guide post mounted in each of said channel members respectively;

transversely disposed unitary carriage means having projections extending into said channel members, said projections being journaled on said guide posts for sliding therealong, and said carriage means adapted to carry a cabinet exteriorly of the wall; and

a motor-driven chain and sprocket system mounted on said frame means for sliding the carriage means along the guide posts, said system including a pair of aligned sprockets disposed generally in a plane located between said channel members, and a link chain trained about said pair of sprockets and connected to said carriage means. 

1. Unitary actuating means for lowering and raising a cabinet and the like, comprising: unitary frame means including a pair of interconnected parallel channel side members disposable substantially vertically between the facing sides of a pair of studs in a wall of a housing construction, each member having a laterally extending flange securable to said wall; a vertical guide post mounted in each of said channel members respectively; transversely disposed unitary carriage means having projections extending into said channel members, said projections being journaled on said guide posts for sliding therealong, and said carriage means adapted to carry a cabinet exteriorly of the wall; and a motor-driven chain and sprocket system mounted on said frame means for sliding the carriage means along the guide posts, said system including a pair of aligned sprockets disposed generally in a plane located between said channel members, and a link chain trained about said pair of sprockets and connected to said carriage means. 